copy an entire txt file to a c++ string

Question

Is there any function that copies a txt file to disk and transfers it whole to a string, without copying character by character in c++?

Answer 1

Exactly as you’re talking you don’t have, but something close does. It actually has a set of tools for accessing files. You must study and master them all to ride the way you wish.

Behold ifstream.

Answer 2

You can create an instance of std::string from a std::ifstream, look at you:

#include <iostream>
#include <string>
#include <fstream>
#include <streambuf>

using namespace std;

int main( void )
{
    /* Abre Arquivo texto para leitura */
    ifstream ifs("arquivo.txt");

    /* Constroi string */
    string str((istreambuf_iterator<char>(ifs)), istreambuf_iterator<char>());

    /* Exibe string */
    cout << str << endl;

    return 0;
}

Simplifying in a single function:

#include <iostream>
#include <string>
#include <fstream>
#include <streambuf>

using namespace std;

string ler_arquivo( const string& arq )
{
    ifstream ifs(arq.c_str());
    string str((istreambuf_iterator<char>(ifs)), istreambuf_iterator<char>());
    return str;
}

int main( void )
{
    string str = ler_arquivo( "arquivo.txt" );
    cout << str << endl;
    return 0;
}